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![[Figure 1]](hi5597fig1mag.jpg)
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Figure 1
The differences between a model FEFF calculation and DEXA calculations using the explicit difference (solid line) and Taylor expansion (dashed line) formalisms in the k-range commonly measured on ID24. The explicit difference formalism yields smaller residuals, though in absolute terms each plot is less than 1% of the model spectrum amplitude. The model consisted of three Fe atoms spaced equidistantly at 3 Å intervals along a line parallel to the presumed X-ray polarization vector P (a spacing comparable with the Fe lattice parameter). The central atom was taken to be the absorbing atom, with the outer two then forming a single scattering shell. Three calculations were performed with FEFF: one for the unstrained case, one for a strain of 1000 p.p.m. parallel to P, and one for a 1000 p.p.m. strain perpendicular to P. The difference between these last two spectra gave the model DiffEXAFS. The information from the unstrained case was supplied to DEXA as a reference structure. |
![[Figure 1]](hi5597fig1.jpg)
 | JOURNAL OF SYNCHROTRON RADIATION |
ISSN: 1600-5775
